Phase Ib Study of the Safety, Tolerance and Activity on Plasma Viremia of Multiple Dose SC rhuIL-10 (SCH 52000) Administration in HIV-Positive Individuals with CD4 Counts >200/ (L. Current treatment for HIV infection is aimed at suppressing the virus (HIV) and managing the symptoms and complications that accompany this infection. The body's immune system (natural defense) is believed to be important in controlling the activity of HIV. Interleukin-10 (IL-10) is a protein substance made by the body's immune system that may affect immune function. IL-10 has been shown to induce a transient and mild decrease of HIV in the blood. For this reason, IL-10 may be of use in the treatment of HIV infection, especially when antiviral drugs alone do not completely suppress HIV replication. This is a randomized, double- blind study of 3 doses of rhuIL-10 in HIV-infected patients with more than 200 CD4 cells and HIV RNA >4,000 copies/ml. IL-10 at 1.,0, 4.0, or 8.0 mcg/kg (or placebo) will be given for four weeks. Endpoints include changes in HIV RNA, CD4 cells and cytokine production.